Add garbage collection for shared extensions on Chrome OS

chrome/browser/extensions/extension_assets_manager_chromeos.cc

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/extension_assets_manager_chromeos.h"
 
 #include <map>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/memory/singleton.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/sequenced_task_runner.h"
 #include "base/sys_info.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/chromeos/login/users/user_manager.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chromeos/chromeos_switches.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/file_util.h"
 #include "extensions/common/manifest.h"
 
 using content::BrowserThread;
 
 namespace extensions {
 namespace {
 
-// A dictionary that maps shared extension IDs to version/paths/users.
-const char kSharedExtensions[] = "SharedExtensions";
-
-// Name of path attribute in shared extensions map.
-const char kSharedExtensionPath[] = "path";
-
-// Name of users attribute (list of user emails) in shared extensions map.
-const char kSharedExtensionUsers[] = "users";
+// Path to shared extensions install dir.
+const char kSharedExtensionsDir[] = "/var/cache/shared_extensions";
 
 // Shared install dir overrider for tests only.
 static const base::FilePath* g_shared_install_dir_override = NULL;
 
 // This helper class lives on UI thread only. Main purpose of this class is to
 // track shared installation in progress between multiple profiles.
 class ExtensionAssetsManagerHelper {
  public:
   // Info about pending install request.
   struct PendingInstallInfo {
@@ skipping 55 matching lines @@
   // Queue of pending installs in progress.
   typedef std::map<InstallItem, std::vector<PendingInstallInfo> > InstallQueue;
 
   InstallQueue install_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAssetsManagerHelper);
 };
 
 }  // namespace
 
-// Path to shared extensions install dir.
-const char ExtensionAssetsManagerChromeOS::kSharedExtensionsDir[] =
-    "/var/cache/shared_extensions";
+const char ExtensionAssetsManagerChromeOS::kSharedExtensions[] =
+    "SharedExtensions";
+
+const char ExtensionAssetsManagerChromeOS::kSharedExtensionPath[] = "path";
+
+const char ExtensionAssetsManagerChromeOS::kSharedExtensionUsers[] = "users";
 
 ExtensionAssetsManagerChromeOS::ExtensionAssetsManagerChromeOS() { }
 
 ExtensionAssetsManagerChromeOS::~ExtensionAssetsManagerChromeOS() {
   if (g_shared_install_dir_override) {
     delete g_shared_install_dir_override;
     g_shared_install_dir_override = NULL;
   }
 }
 
@@ skipping 47 matching lines @@
     // In some test extensions installed outside local_install_dir emulate
     // previous behavior that just do nothing in this case.
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
         base::Bind(&ExtensionAssetsManagerChromeOS::MarkSharedExtensionUnused,
                    id,
                    profile));
   }
 }
 
 // static
+base::FilePath ExtensionAssetsManagerChromeOS::GetSharedInstallDir() {
+  if (g_shared_install_dir_override)
+    return *g_shared_install_dir_override;
+  else
+    return base::FilePath(kSharedExtensionsDir);
+}
+
+// static
+bool ExtensionAssetsManagerChromeOS::CleanUpSharedExtensions(
+    std::multimap<std::string, base::FilePath>* live_extension_paths) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  PrefService* local_state = g_browser_process->local_state();
+  // It happens in many unit tests.
+  if (!local_state)
+    return false;
+
+  DictionaryPrefUpdate shared_extensions(local_state, kSharedExtensions);
+  std::vector<std::string> extensions;
+  extensions.reserve(shared_extensions->size());
+  for (base::DictionaryValue::Iterator it(*shared_extensions);
+       !it.IsAtEnd(); it.Advance()) {
+    extensions.push_back(it.key());
+  }
+
+  for (std::vector<std::string>::iterator it = extensions.begin();
+       it != extensions.end(); it++) {
+    base::DictionaryValue* extension_info = NULL;
+    if (!shared_extensions->GetDictionary(*it, &extension_info)) {
+      NOTREACHED();
+      return false;
+    }
+    if (!CleanUpExtension(*it, extension_info, live_extension_paths)) {
+      return false;
+    }
+    if (!extension_info->size())
+      shared_extensions->RemoveWithoutPathExpansion(*it, NULL);
+  }
+
+  return true;
+}
+
+// static
 void ExtensionAssetsManagerChromeOS::SetSharedInstallDirForTesting(
     const base::FilePath& install_dir) {
   DCHECK(!g_shared_install_dir_override);
   g_shared_install_dir_override = new base::FilePath(install_dir);
 }
 
 // static
 base::SequencedTaskRunner* ExtensionAssetsManagerChromeOS::GetFileTaskRunner(
     Profile* profile) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   ExtensionService* extension_service =
       ExtensionSystem::Get(profile)->extension_service();
   return extension_service->GetFileTaskRunner();
 }
 
 // static
-base::FilePath ExtensionAssetsManagerChromeOS::GetSharedInstallDir() {
-  if (g_shared_install_dir_override)
-    return *g_shared_install_dir_override;
-  else
-    return base::FilePath(kSharedExtensionsDir);
-}
-
-// static
 bool ExtensionAssetsManagerChromeOS::CanShareAssets(
     const Extension* extension) {
   if (!CommandLine::ForCurrentProcess()->HasSwitch(
           chromeos::switches::kEnableExtensionAssetsSharing)) {
     return false;
   }
 
   // Chrome caches crx files for installed by default apps so sharing assets is
   // also possible. User specific apps should be excluded to not expose apps
   // unique for the user outside of user's cryptohome.
   return Manifest::IsExternalLocation(extension->location());
 }
 
 // static
 void ExtensionAssetsManagerChromeOS::CheckSharedExtension(
     const std::string& id,
     const std::string& version,
     const base::FilePath& unpacked_extension_root,
     const base::FilePath& local_install_dir,
     Profile* profile,
     InstallExtensionCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
+  const std::string& user_id = profile->GetProfileName();
+  chromeos::UserManager* user_manager = chromeos::UserManager::Get();
+  if (!user_manager) {
+    NOTREACHED();
+    return;
+  }
+
+  if (user_manager->IsUserNonCryptohomeDataEphemeral(user_id) ||
+      !user_manager->IsLoggedInAsRegularUser()) {
+    // Don't cache anything in shared location for ephemeral user or special
+    // user types.
+    ExtensionAssetsManagerChromeOS::GetFileTaskRunner(profile)->PostTask(
+        FROM_HERE,
+        base::Bind(&ExtensionAssetsManagerChromeOS::InstallLocalExtension,
+                   id,
+                   version,
+                   unpacked_extension_root,
+                   local_install_dir,
+                   callback));
+    return;
+  }
+
   PrefService* local_state = g_browser_process->local_state();
   DictionaryPrefUpdate shared_extensions(local_state, kSharedExtensions);
   base::DictionaryValue* extension_info = NULL;
   base::DictionaryValue* version_info = NULL;
   base::ListValue* users = NULL;
   std::string shared_path;
   if (shared_extensions->GetDictionary(id, &extension_info) &&
       extension_info->GetDictionaryWithoutPathExpansion(
           version, &version_info) &&
       version_info->GetString(kSharedExtensionPath, &shared_path) &&
       version_info->GetList(kSharedExtensionUsers, &users)) {
     // This extension version already in shared location.
-    const std::string& user_name = profile->GetProfileName();
     size_t users_size = users->GetSize();
     bool user_found = false;
     for (size_t i = 0; i < users_size; i++) {
       std::string temp;
-      if (users->GetString(i, &temp) && temp == user_name) {
+      if (users->GetString(i, &temp) && temp == user_id) {
         // Re-installation for the same user.
         user_found = true;
         break;
       }
     }
     if (!user_found)
-      users->AppendString(user_name);
+      users->AppendString(user_id);
 
     // unpacked_extension_root will be deleted by CrxInstaller.
     ExtensionAssetsManagerChromeOS::GetFileTaskRunner(profile)->PostTask(
         FROM_HERE,
         base::Bind(callback, base::FilePath(shared_path)));
   } else {
     // Desired version is not found in shared location.
     ExtensionAssetsManagerHelper* helper =
         ExtensionAssetsManagerHelper::GetInstance();
     if (helper->RecordSharedInstall(id, version, unpacked_extension_root,
@@ skipping 131 matching lines @@
         NOTREACHED();
         continue;
       }
       ExtensionAssetsManagerChromeOS::GetFileTaskRunner(profile)->PostTask(
           FROM_HERE,
           base::Bind(&ExtensionAssetsManagerChromeOS::DeleteSharedVersion,
                      base::FilePath(shared_path)));
       extension_info->RemoveWithoutPathExpansion(*it, NULL);
     }
   }
-  // Don't remove extension dir in shared location. It will be removed by GC
-  // when it is safe to do avoid race condition between uninstall extension
-  // used by single user and installing the same extension for other user.
+  if (!extension_info->size()) {
+    shared_extensions->RemoveWithoutPathExpansion(id, NULL);
+    // Don't remove extension dir in shared location. It will be removed by GC
+    // when it is safe to do avoid race condition between uninstall extension
+    // used by single user and installing the same extension for other user.
+  }
 }
 
 // static
 void ExtensionAssetsManagerChromeOS::DeleteSharedVersion(
     const base::FilePath& shared_version_dir) {
   CHECK(GetSharedInstallDir().IsParent(shared_version_dir));
   base::DeleteFile(shared_version_dir, true);  // recursive.
 }
 
+// static
+bool ExtensionAssetsManagerChromeOS::CleanUpExtension(
+    const std::string& id,
+    base::DictionaryValue* extension_info,
+    std::multimap<std::string, base::FilePath>* live_extension_paths) {
+  chromeos::UserManager* user_manager = chromeos::UserManager::Get();
+  if (!user_manager) {
+    NOTREACHED();
+    return false;
+  }
+
+  std::vector<std::string> versions;
+  versions.reserve(extension_info->size());
+  for (base::DictionaryValue::Iterator it(*extension_info);
+       !it.IsAtEnd(); it.Advance()) {
+    versions.push_back(it.key());
+  }
+
+  for (std::vector<std::string>::const_iterator it = versions.begin();
+       it != versions.end(); it++) {
+    base::DictionaryValue* version_info = NULL;
+    base::ListValue* users = NULL;
+    std::string shared_path;
+    if (!extension_info->GetDictionaryWithoutPathExpansion(*it,
+                                                           &version_info) ||
+        !version_info->GetList(kSharedExtensionUsers, &users) ||
+        !version_info->GetString(kSharedExtensionPath, &shared_path)) {
+      NOTREACHED();
+      return false;
+    }
+
+    size_t num_users = users->GetSize();
+    for (size_t i = 0; i < num_users; i++) {
+      std::string user_id;
+      if (!users->GetString(i, &user_id)) {
+        NOTREACHED();
+        return false;
+      }
+      const chromeos::User* user = user_manager->FindUser(user_id);
+      bool not_used = false;
+      if (!user) {
+        not_used = true;
+      } else if (user->is_logged_in()) {
+        // For logged in user also check that this path is actually used as
+        // installed extension or as delayed install.
+        Profile* profile = user_manager->GetProfileByUser(user);
+        ExtensionPrefs* extension_prefs = ExtensionPrefs::Get(profile);
+        if (!extension_prefs || extension_prefs->pref_service()->ReadOnly())
+          return false;
+
+        scoped_ptr<ExtensionInfo> info =
+            extension_prefs->GetInstalledExtensionInfo(id);
+        if (!info || info->extension_path != base::FilePath(shared_path)) {
+          info = extension_prefs->GetDelayedInstallInfo(id);
+          if (!info || info->extension_path != base::FilePath(shared_path)) {
+            not_used = true;
+          }
+        }
+      }
+
+      if (not_used) {
+        users->Remove(i, NULL);
+
+        i--;
+        num_users--;
+        continue;
+      }
+    }
+
+    if (num_users) {
+      live_extension_paths->insert(
+          std::make_pair(id, base::FilePath(shared_path)));
+    } else {
+      version_info->RemoveWithoutPathExpansion(*it, NULL);
+    }
+  }
+
+  return true;
+}
+
 }  // namespace extensions